Deriver running in a web page in a web browser (no installation required)


The Deriver Application can run in a web page, without needing any installation. This means that Deriver can run on any computer that can run a web browser (i.e. pretty much any computer). The Application has several useful features. It can save, and re-open, partially or entirely completed work.  New exercises, or examinations, can be written by an instructor and opened by students. There is printing. It can run a variety of logical systems, from different versions of propositional and predicate calculus, to trees, modal logic, set theory, lambda calculus etc.

[5/26/22 There is a new version of this. The underlying logic systems are the same, but the hosting Webswing is updated to 22.1 which is a 2022 version. The installation has not been fully tested yet, that is ongoing. But Deriver should launch faster, and generally be a little bit smoother and better. If you wish to try, or use, that, here is the link Deriver as a Web Application The Username is 'logic' and the pwd is 'logic'. You'd probably want to Zoom in a couple or three times off the Browser View Menu to make the application a little larger, or you can click on the expand icon 

Expand Icon

to fill the web page.

Bugs— eccentricities

1. Saving. Typically a User will save their work every 5-10 minutes using the File Menu command Save (or Cntr-S). But here, the first Save will save but subsequent Saves, in the same session, will not. (What is happening, in the background, is that the server saves, but it won't reliably push those to the client machine. ) Workaround:- Use Save As, also from the File Menu. This will work but will involved you with adjusting the file name to write over your previous version. Sorry!



Please click on one of

Deriver will ask you for a User name and password, which are 'logic' and 'logic' . When it launches it will take about 10 seconds to display a splash-screen, then another 15 seconds before Deriver itself appears.

It will appear as a 'window' (or 'browser') within a web page. Sometimes it is more convenient for Deriver to fill that web page (to make it is large as it can be, and to make re-sizing easier). Other times it is more convenient not to do this (when, for example, you are going to have two or more instances of Deriver open and be editing backwards are forwards between them). You can fill or not fill the web page by clicking the relevant icons on the title bar of Deriver (it is just like going full screen or not full screen on an ordinary desktop application). If you expand Deriver, it will give you more space to work with, but it will not change any font sizes. If you would like the fonts to be larger or smaller just Zoom in or out off your web browser's View menu.

To go further, please go to Fast Start on the Application (for Instructors)

To try some exercises as examples, you have choices.

  • you can download the zipped folders 10 Propositional Exercises (Gentzen syntax) or 15 Predicate Exercises (Gentzen syntax) Expand the compressed folders. Then open individual logic files in Deriver using 'Open Logic File' off the File menu.
  • not everyone is keen on downloading and opening zipped files. There are alternatives. Deriver's logic files themselves are just text (they are a mix of HTML and XML). If you click on any of these links individually, your web browser (Chrome, Safari, Brave, Firefox, Edge, etc) will open the logic files as text and you can inspect them. If you then want to open any of them in Deriver, there are two ways. Perhaps the easiest is to copy the relevant link, then use the link in Deriver to 'Open Web Page' off the File menu. A second way is to use your web browser (Chrome, Safari, Brave, Firefox, Edge, etc) to save the web page to your computer (as, say PropEx3.lgc) then use 'Open Logic File' off the File menu in Deriver to open, say, PropEx3.lgc . Here are a couple of example files using the Gentzen syntax.



The above illustrative examples are using the 'Gentzen' system of propositional and predicate logic (its syntax and its rules). It is possible that the version of Deriver that you are running is not using that system. For example, you might be using a communal computer in a University lab and the person before you was using a different system. You can check what Deriver is running from the Title Bar, or from the Preferences, and, if needed, set the preferences exactly as you would like. Configuring the Deriver Application Using the Preferences  In this case, you would probably want the parser set to 'gentzen' and the paletteText set to 'default'.

Deriver here uses Webswing technology. Thank you to them for that.